1  /* Test for ungetc bugs.  */
       2  
       3  #include <stdio.h>
       4  #include <stdlib.h>
       5  #include <unistd.h>
       6  
       7  #undef assert
       8  #define assert(x) \
       9    if (!(x)) \
      10      { \
      11        fputs ("test failed: " #x "\n", stderr); \
      12        retval = 1; \
      13        goto the_end; \
      14      }
      15  
      16  int
      17  main (int argc, char *argv[])
      18  {
      19    char name[] = "/tmp/tst-ungetc.XXXXXX";
      20    FILE *fp = NULL;
      21    int retval = 0;
      22    int c;
      23    char buffer[64];
      24  
      25    int fd = mkstemp (name);
      26    if (fd == -1)
      27      {
      28        printf ("mkstemp failed: %m\n");
      29        return 1;
      30      }
      31    close (fd);
      32    fp = fopen (name, "w");
      33    assert (fp != NULL)
      34    fputs ("bla", fp);
      35    fclose (fp);
      36    fp = NULL;
      37  
      38    fp = fopen (name, "r");
      39    assert (fp != NULL);
      40    assert (ungetc ('z', fp) == 'z');
      41    assert (getc (fp) == 'z');
      42    assert (getc (fp) == 'b');
      43    assert (getc (fp) == 'l');
      44    assert (ungetc ('m', fp) == 'm');
      45    assert (getc (fp) == 'm');
      46    assert ((c = getc (fp)) == 'a');
      47    assert (getc (fp) == EOF);
      48    assert (ungetc (c, fp) == c);
      49    assert (feof (fp) == 0);
      50    assert (getc (fp) == c);
      51    assert (getc (fp) == EOF);
      52    fclose (fp);
      53    fp = NULL;
      54  
      55    fp = fopen (name, "r");
      56    assert (fp != NULL);
      57    assert (getc (fp) == 'b');
      58    assert (getc (fp) == 'l');
      59    assert (ungetc ('b', fp) == 'b');
      60    assert (fread (buffer, 1, 64, fp) == 2);
      61    assert (buffer[0] == 'b');
      62    assert (buffer[1] == 'a');
      63  
      64  the_end:
      65    if (fp != NULL)
      66      fclose (fp);
      67    unlink (name);
      68  
      69    return retval;
      70  }